JPH053909B2 - - Google Patents
Info
- Publication number
- JPH053909B2 JPH053909B2 JP60053600A JP5360085A JPH053909B2 JP H053909 B2 JPH053909 B2 JP H053909B2 JP 60053600 A JP60053600 A JP 60053600A JP 5360085 A JP5360085 A JP 5360085A JP H053909 B2 JPH053909 B2 JP H053909B2
- Authority
- JP
- Japan
- Prior art keywords
- sensor
- current value
- oxygen
- limiting current
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000001301 oxygen Substances 0.000 claims description 22
- 229910052760 oxygen Inorganic materials 0.000 claims description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 19
- 230000006866 deterioration Effects 0.000 claims description 7
- 238000002405 diagnostic procedure Methods 0.000 claims description 3
- 238000004092 self-diagnosis Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 3
- 238000003745 diagnosis Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 239000007784 solid electrolyte Substances 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 229910002076 stabilized zirconia Inorganic materials 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の詳細な説明】
＜産業上の利用分野＞
本発明は、限界電流方式の酸素センサーの劣化
を診断する自己診断方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a self-diagnosis method for diagnosing deterioration of a limiting current type oxygen sensor.
＜従来の技術＞
限界電流方式の酸素センサーは、固体電解質の
酸素イオン導電板を用いて構成され、印加電圧に
対する出力電流特性の平坦部（ある印加電圧の範
囲で印加電圧が増加しても出力電流が一定となる
フラツト領域）のなす電流値（限界電流値）を読
んで酸素の濃度を測定するものである。<Conventional technology> A limiting current type oxygen sensor is constructed using an oxygen ion conductive plate made of a solid electrolyte, and has a flat part in the output current characteristics with respect to the applied voltage (the output does not change even if the applied voltage increases within a certain applied voltage range). The oxygen concentration is measured by reading the current value (limit current value) formed in a flat region where the current is constant.
このセンサーをより具体的に示すと、第２図の
如くで、同図において、１は酸素イオン導電板で
あり、安定化ジルコニア（ZrO2）等の固体電解
質からなる。この導電板１の両面には白金等の多
孔質金属からなる電極２，２′が取付けてあり、
その一方（図中、上方）の電極２′側には、隔離
室Ｒを形成するキヤツプ状のカバー３が固定して
ある。このカバー３の頂部中央にはこの頂部を貫
通する微小径の拡散孔４が設けてある。そして、
上記両電極２，２′間には又電源５と電流計Ａを
直列に、電圧計Ｖを並列に接続してある。 This sensor is shown in more detail in FIG. 2, in which reference numeral 1 denotes an oxygen ion conductive plate, which is made of a solid electrolyte such as stabilized zirconia (ZrO 2 ). Electrodes 2 and 2' made of porous metal such as platinum are attached to both sides of the conductive plate 1.
A cap-shaped cover 3 forming an isolation chamber R is fixed to one side (upper side in the figure) of the electrode 2'. At the center of the top of this cover 3, there is provided a diffusion hole 4 with a minute diameter passing through the top. and,
A power source 5 and an ammeter A are connected in series and a voltmeter V is connected in parallel between the two electrodes 2 and 2'.
この酸素センサーにより、被測定気体中の酸素
濃度を測定するには、電源５の印加電圧を徐々に
増していくと、電流計Ａの出力電流値は、模式的
に示すと、第３図の折れ線６のような電圧−電流
特性曲線を示す。この折れ線６中における平坦部
６ａのなす部分の電流値（限界電流値1l）を読む
ことにより、この値に対応した被測定気体中の酸
素濃度を知ることがである。 To measure the oxygen concentration in the gas to be measured using this oxygen sensor, when the applied voltage of the power source 5 is gradually increased, the output current value of the ammeter A is shown schematically in Fig. 3. A voltage-current characteristic curve like a polygonal line 6 is shown. By reading the current value (limit current value 1l) at the portion formed by the flat portion 6a in this polygonal line 6, the oxygen concentration in the gas to be measured corresponding to this value can be found.
実際のセンサーにおいては、予め種々の酸素濃
度に対応する限界電流値Ilが求められているた
め、測定時には、特性曲線６の平坦部６ａの範囲
内の任意の１個所に測定印加電圧Vsを印加すれ
ば、そのときの限界電流値Ilから直ちに酸素濃度
が求められる。 In the actual sensor, the limiting current value Il corresponding to various oxygen concentrations is determined in advance, so at the time of measurement, the measurement applied voltage Vs is applied to any one point within the range of the flat part 6a of the characteristic curve 6. Then, the oxygen concentration can be immediately determined from the limiting current value Il at that time.
＜発明が解決しようとする問題点＞
ところが、この種の酸素センサーは、三相界面
の減少等、種々の原因で劣化することがある。そ
こで、このような劣化に気付かずに使用している
と、誤つた酸素濃度の測定が行われ、ときには重
大な事故を招く虞がある。<Problems to be Solved by the Invention> However, this type of oxygen sensor may deteriorate due to various causes such as a decrease in the number of three-phase interfaces. Therefore, if the device is used without noticing such deterioration, the oxygen concentration may be measured incorrectly, which may lead to a serious accident.
このため、センサーの使用にあたつては、細心
の注意を払つた診断が必要で、従来より種々の診
断方法が提案されている。 Therefore, when using the sensor, careful diagnosis is required, and various diagnostic methods have been proposed.
本発明は、このような背景のもとになされた診
断方法の一つで、極めて簡便な方法で診断できる
ようにしたものである。 The present invention is one of the diagnostic methods devised against this background, and allows diagnosis to be performed using an extremely simple method.
＜問題点を解決するための手段＞
即ち、本発明の特徴とする点は、限界電流方式
の酸素センサーにおいて、センサーをオン
（ON）にしたとき（即ち、電圧印加を開始した
とき）、センサーが正常の場合、測定値が安定す
るまでの間に、後述のオーバーシユート（Over
−Shoot）現象が現れることに着目し、当該オー
バーシユート現象の程度、特に有無により、劣化
を判断するようにした点にある。<Means for solving the problem> That is, the feature of the present invention is that in a limiting current type oxygen sensor, when the sensor is turned on (that is, when voltage application is started), the sensor is normal, the overshoot (described later) will occur until the measured value stabilizes.
-Shoot) phenomenon appears, and deterioration is determined based on the degree of the overshoot phenomenon, especially the presence or absence of the phenomenon.
この点をより詳しく説明すると、第１図の如く
である。 This point will be explained in more detail as shown in FIG.
つまり、正常に動作する限界電流方式の酸素セ
ンサーの場合、当該センサーをオン（ON）にす
ると、センサー・キヤビテイ内の酸素が先ず排出
されるため、測定値が平坦（図中のフラツト領域
７）となつて安定な限界電流値Ilを示すまでの間
に、図示の***部分８に示すような限界電流値Il
より大きな電流値Iaを示す部分がある。この***
部分８の電流増大現象がオーバーシユート現象で
ある。 In other words, in the case of a normally operating limiting current type oxygen sensor, when the sensor is turned on, the oxygen in the sensor cavity is first exhausted, so the measured value is flat (flat area 7 in the figure). Until the stable limiting current value Il is reached, the limiting current value Il as shown in the raised portion 8 in the figure increases.
There is a part that shows a larger current value Ia. This current increase phenomenon in the raised portion 8 is an overshoot phenomenon.
このオーバーシユート現象は、センサーが劣化
（抵抗値の増加等）すると、前記第３図の電圧−
電流特性曲線６の立ち上り部分（電圧−電流比例
領域）６ｂの立上り性が悪くなつて、現れなくな
る。 This overshoot phenomenon occurs when the sensor deteriorates (increase in resistance, etc.) and the voltage -
The rising characteristic of the rising portion (voltage-current proportional region) 6b of the current characteristic curve 6 deteriorates and no longer appears.
このため、このオーバーシユート現象の有無を
センサー劣化の目安とすることができる。 Therefore, the presence or absence of this overshoot phenomenon can be used as a measure of sensor deterioration.
＜作用＞
従つて、本発明では、センサーオン（ON）し
たとき、当初の測定電流値がその後の安定電流値
（限界電流値Il）より、大きいときには、正常な
センサーと簡単に判断することができる。<Function> Therefore, in the present invention, when the sensor is turned on (ON) and the initially measured current value is larger than the subsequent stable current value (limit current value Il), it can be easily determined that the sensor is normal. can.
逆に、上記関係がないときには、劣化が進行し
ていると、判断することができる。 Conversely, if the above relationship does not exist, it can be determined that deterioration is progressing.
＜実施例＞
前記第２図に示すセンサーで、予め正常動作の
確認されたものについて、通常の測定時に印加す
る測定印加電圧Vs、例えば1.6Vを印加して、そ
の出力電流を時間の経過と共に読み取つた。尚、
被測定気体中の酸素濃度は、20.9％である。<Example> For the sensor shown in FIG. 2, whose normal operation has been confirmed in advance, a measurement applied voltage Vs, for example 1.6V, which is applied during normal measurement, is applied, and the output current is measured over time. I read it. still,
The oxygen concentration in the gas to be measured is 20.9%.
初期の電流値は1.5ｍＡを示し、暫くして（ｔ
＝100秒）、0.5ｍＡの安定した限界電流値Ilを示し
た。この0.5ｍＡの限界電流値Ilは丁度酸素濃度
20.9％に対応していた。 The initial current value was 1.5 mA, and after a while (t
= 100 seconds), and showed a stable limiting current value Il of 0.5 mA. This 0.5mA limiting current value Il is exactly the oxygen concentration.
It corresponded to 20.9%.
一方、明らかに劣化の分かつているセンサーに
ついて、同様の試験を行つたところ、初期電流値
の増大は認められなかつた。 On the other hand, when a similar test was conducted on a sensor that was clearly degraded, no increase in the initial current value was observed.
＜発明の効果＞
本発明によれば、以上の説明から明らかなよう
に、単にオーバーシユート現象の有無によつて、
極めて簡単、且つ迅速にセンサーの劣化を診断す
ることができる優れた自己診断方法を提供するこ
とができる。<Effects of the Invention> According to the present invention, as is clear from the above explanation, simply depending on the presence or absence of the overshoot phenomenon,
It is possible to provide an excellent self-diagnosis method that can extremely simply and quickly diagnose sensor deterioration.
第１図は本発明方法で利用するオーバーシユー
ト現象を示す時間−電流特性曲線図、第２図は限
界電流方式の酸素センサーの一例を示す縦断面
図、第３図は第２図の酸素センサーの示す電圧−
電流曲線図である。
図中、Vs……印加電圧、Il……限界電流値、７
……時間−電流特性曲線、８……オーバーシユー
ト現象部分。
Fig. 1 is a time-current characteristic curve diagram showing the overshoot phenomenon used in the method of the present invention, Fig. 2 is a vertical cross-sectional view showing an example of a limiting current type oxygen sensor, and Fig. 3 is an oxygen Voltage indicated by sensor -
It is a current curve diagram. In the figure, Vs...applied voltage, Il...limiting current value, 7
...Time-current characteristic curve, 8...Overshoot phenomenon part.
Claims (1)
す限界電流値を読んで酸素濃度を測定する酸素セ
ンサーにおいて、センサー初期駆動時に現れるオ
ーバーシユート現象の程度により、センサーの劣
化を診断する酸素センサーの自己診断方法。1 In an oxygen sensor that measures oxygen concentration by reading the limiting current value formed by the flat part of the output current characteristics with respect to the applied voltage, the oxygen sensor self-diagnosis is used to diagnose sensor deterioration based on the degree of overshoot phenomenon that appears when the sensor is initially activated. Diagnostic method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60053600A JPS61212753A (en) | 1985-03-18 | 1985-03-18 | Self-diagnosis of oxygen sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60053600A JPS61212753A (en) | 1985-03-18 | 1985-03-18 | Self-diagnosis of oxygen sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61212753A JPS61212753A (en) | 1986-09-20 |
| JPH053909B2 true JPH053909B2 (en) | 1993-01-18 |
Family
ID=12947369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60053600A Granted JPS61212753A (en) | 1985-03-18 | 1985-03-18 | Self-diagnosis of oxygen sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61212753A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03134552A (en) * | 1989-10-20 | 1991-06-07 | Hitachi Ltd | Detecting apparatus with self-calibration function |
| WO2006022003A1 (en) * | 2004-08-26 | 2006-03-02 | Figaro Engineering Inc. | Electrochemical gas sensor self-diagnosis method and gas sensor |
| US7090755B2 (en) | 2004-10-28 | 2006-08-15 | Figaro Engineering Inc. | Gas detecting device with self-diagnosis for electrochemical gas sensor |
| US7464585B2 (en) * | 2005-07-21 | 2008-12-16 | United Technologies Corporation | Method and apparatus for sensing integrity degradation in turbine engine components |
| JP2016061625A (en) * | 2014-09-17 | 2016-04-25 | 株式会社デンソー | Sensor control device |
| WO2023026899A1 (en) * | 2021-08-25 | 2023-03-02 | 日本碍子株式会社 | Gas sensor |
-
1985
- 1985-03-18 JP JP60053600A patent/JPS61212753A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61212753A (en) | 1986-09-20 |
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